AMESBURY — Communities across the nation have found the same mysterious residue in their fluoride systems that caused Amesbury to shut down its water fluoridation program, but a federal health agency said the residue is safe.

Kip Duchon, national fluoridation engineer for the federal Centers for Disease Control, said residents shouldn’t worry about the safety of a Chinese-made fluoride product used by many communities.

Though Duchon admitted he and officials from the American Water Works Association (AWWA) have received complaints from a number of those currently purchasing the powder form of the mineral, the fact that it won’t dissolve or “handle” as well as the American-produced mineral once did does not mean the products are unsafe, he said.

“The safety, along with the purity and contaminants of the products, is verified and validated by independent certification entities and are not a concern,” said Duchon. “The concern that some water facility operators have expressed are related to the material handling properties.”

The town discontinued fluoridating the town’s water supply in April, citing concerns that approximately 40 percent of the material from new Chinese suppliers was not dissolving. DPW Director Rob Desmarais said there are no plans to resume fluoridation given the fact that current supplies don’t meet the town’s standards.

“We don’t know what the stuff is,” said Desmarais last week of the insoluble material gumming up the works in Amesbury.

According to Duchon, until 2006 nearly 100 percent of the sodium fluoride produced and distributed to cities and towns came from an American manufacturer. That company was forced out of business, he said, unable to compete with the low prices being offered by Chinese and Asian companies entering the market.

Newburyport Water Superintendent Paul Colby said he shares Desmarais’ opinion that supplies from China are of a poorer quality than the U.S. and Japanese products that were once widely available.

“It’s not as good as fluoride used to be a few years ago,” said Colby. “The main change is that’s it’s much more powdery. We’re finding different ways to work around it.”

Whereas in past years the raw soluble sodium fluoride Newburyport used was added in 150-pound increments, today Colby said now it is used in 50-pound increments to not overwhelm the city’s system.

“Most of the sodium fluoride we get today comes from China,” said Colby. “What we’re using currently in Newburyport comes from China. Years ago it used to come from Japan.”

Colby said he feels confident knowing the material is approved for use by AWWA, and he said Newburyport is getting around the solubility issue by more frequently maintaining and cleaning their saturators.

Aside from serving as the Centers for Disease Control’s foremost authority and advocate on the health benefits of fluoridating water supplies, Duchon also serves as spokesman for the AWWA Fluoride Standards Committee — the nation’s volunteer regulatory body, which recently sent out questionnaires to municipalities inquiring about their experience with the fluoride others have been complaining about.

Duchon wouldn’t specify how many of the 300 or so questionnaire respondents complained of the quality, but he classified it as a minority.

Chairman of the ARRA Fluoride Standards Committee Dave Heumann confirmed he’d received complaints on the product from other municipalities.

“We have been aware of this for some time,” said Heumann. “We’re working on it. These kinds of things take research and time.”

“My preliminary conclusion is that this seems to be a limited problem at some water plants, but is not widespread,” wrote Duchon in an e-mail. “We will continue to accept survey results and hope to better understand what are the factors that cause some facilities to experience handling problems. We are also conducting our own testing of the products including samples that have been sent to us from water plants reporting handling problems and are attempting to better characterize these products.”

Local opinions

In the meantime, members of the public are voicing their own opinions on Amesbury’s decision to discontinue fluoridation — with some residents arguing against the idea of adding fluoride, especially if there is concern over its composition, and others voicing disapproval that fluoridation isn’t a priority for Amesbury.

“Our community is suffering because this is a very important thing,” said John Rizza, an Amesbury resident and a practicing dentist of 30 years who said he’s seen first-hand how fluoridation of the public water supply has kept cavities at bay. “I’m disappointed with the current Board of Health to take it out without any means of saying we’re going to put it back.”

Rizza is questioning the delivery system Amesbury depends on for fluoridation, which Duchon says is being used by 8 percent of the total number of communities that fluoridate. For the sake of a healthy populace, Rizza is urging the town to consider updating its process to allow residents to continue to reap the benefits of fluoridation.

“Amesbury is placing it in into the system in a very old-fashioned way,” said Rizza. “They get a powder and they dissolve it into the water. One third of cities are still doing it this way, but the majority have switched over to liquid fluoride.”

“Did you know that the chemicals used to fluoridate drinking water (fluorosilicic acid, sodium silicofluoride and sodium fluoride) are industrial waste products from the phosphate fertilizer industry?” wrote Jacqueline Carroll, a nurse practitioner from Newburyport concerned about the toxic properties of the mineral on the human body.

“As a health care provider and a concerned citizen in our community, I am also advocating for the health of my own family. I want fluoride removed from the drinking water in Newburyport — I want the right to refuse fluoride.”